Why is spotlight shining through cube? (Blender 2.80 EEVEE render view)
For any curious about this, here's the nature of the problem and the solution
at Blender bug reports. Turns out it's not a bug, but I had thought it might be,
so to help by reporting it I thought I'd inquire there at Blender bug reports.
https://developer.blender.org/T63768